Cylindrical mortise latch



A 1. E. mom. CYLINDRICAL NIORTISE LATCH.

APPLICATION FILED MAY 2| I92I.

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UN.irans'rA'rnv 'Jonannas EHRHORN maar, or GOrENHaGEN, DENMARK; f

CYLINDRICAL ivron'risELnToH.

iafiafae.v i *l Application filed May 2,

To all whoml t may concern: v

Be it known that I, JOHANNES Erinnern;

HJORT, manufacturer, subjectfot the.y King of Denmark, residing at Copenhagen, Dein `mark, have invented certain new and usef'ul Improvements in Cylindrical Mortise Latchesg. ,Of .Which the fOllOwing is a specification. l

The present invention relatesv to 'such mortise latches, as are used for do,ors,.1"urn1 ture, etc., and are opened by means of a knob or handle. The latch here referred to belongs to the 'known type of such latches in which the mainly cylindrical casing is made `extremely compact in order ,tol render practicable the insertion of the latch into a ycylindrical hole bored in the stile of the door, instead of, as in the case ot the ordinary box-shapedinortise latches, ill a mortise gouged inthe stile, in' the first place the latchY proper .will thereby be much cheaper to manufacture and,`in the second place,4

the jolinery Work required for fitting the latch in position will also be considerably v an,

cheaper and easier.v

Latches of the said known kindhave heretofore not been fitted with aspira] spring for keeping the hub of the knob-spindle and.

thereby, the knob or handle' in normal posi- V tion, as long as thelock is not b'eH-igoperated..V Theobject of' such a spiral spring is to secure vthe knob or handlein such a position, that when turned, it will at once unlatch'the door or, in other words, that thev knobA or handlewill be returned into the normal position by means lof the spiral spring, independently of the position ofthe f latch. This spring is well known from ordi.-

nary locks, but in case of latches to be opened by means of a knob or handle, it Lhas not heretofore been practicable to use a spiral spring', because the construction of the latch has to be very compact, and it is desired to maintain the cylindrical shape so that fitting of the latch Vwill only re-v quire a round (cylindrical) hole to be boredA in the edge of the door. Y Y

By the present invention the advantage Vis attained that cylindrical latches may be provided with a spiral spring by disposing the same between the hub and the latch in 'such a manner, that it will be located in a plane passing through the axis of .the latch casing and so that the axis of the spring will intersect the axis of the latch casing. The latch retains thus its compact shape, and preserves all the advantages presented by Specification of Letters Patent. Patented Api.

192,17. serial 1wS.-/ice,127. i

area-dint@ dwf-nanas fated wahspirai springs, for instance the advantagev thatthe position of the knobor handle will not def f pend on the latch being withdrawn or not, but will always be a. certain definite one,

and the motion of the knob. o r bandiere,-

quiredl in opening or closing thel latchrmay.'

be-made as small as possible by disposing the nose on the hub, whchservcs to withdf'g 5` draw the latch tion, in 'such path .which the said nose must fcllowin during, the unlatching opera-y order to.be moved backwards so farlthat the .latch will be' withdrawnA intoglthe casing,

will be bisected bya plane through 'the axis of 4the hub and at right angle, to the Vlongi-` tudinal axisuof the' latchfcasing.`

`l-lereby a cheap practical light indenni- V Pat latch 'iS.provid@.Ctl ceaibnng the. '21dvantages yofthecylindrical latch with the advantages ofthe ordinary mortise' latch... O11 the drawings' with the coverremoved," l Figathe latch in top. view with the cover 1nY positioinandv U lFig.` l shows .the latch side elevation silsts" of'two partsA symmetrical: about'Y agverf` a manner that the-angular Fig. tithe latch viewedV from its inner end.

tical centralf planegf'the twc'parts being Y shaped in ,snch a manner-as itv appears from Fig-. 'Bthat the' casing,` In easilyY be in serte'dfinto 'a' boredhele. Incontradistinc-r tlOl; t0 the heretcfore known latches cf this kind, the casing .ghas flat'sides, howeverT whereby it` becomes practicable to let the.

moving parts of the` latch be guided Aagainst v the inner face of the casingpproper. 3 is thelatch which has a tail 4t extending back into the casing,` guided by a lug 14, slot 15 `in the top side of the casing.A A similar slot 15 `is provided in the bottom the said extension being which engages a' longl side of the casing. A slot in the latch tailA is yengaged by the upwardly directed finger 6 of the hub 5. The latch is maintained in the latching position by means of a helical spring 7 which is inserted between the inner` face ofthe latch and a fixed cross wall S in the casing.

Immediately behind this cross wall, there is provided a spiral spring' 9, the Vfree end of which engages another finger l0 on the hub, the said finger being thereby pressed down towards the ,bottoml side' ofthe cas- 5,?, neige-ie ing. The knob or handle attached to the hub will therefore always have a tendency to return intoits normal position, independently of the position occupied by the latch proper, all provided that the latch is not at the moment concerned being withdrawn by the drawing, or one half of the casing may f engage into a recess in the front plate alongside the latch, and may thereby be attached to the :ti-ont plate.

Owing to its very compact shape, in respect to width as well as length, this latch weakens the door stile only very slightly. ln the case of heavy stiles, the latch may be inserted in a single bored hole, while in thinner stiles two holes of smaller diameter Y may be bored, one on top of the'other, so

as to correspond to the outer shape of the top and bottom lsides of the casing.

. @wing to its Shape being symmetric about a horizontal plane through its axis, the latch, which is shown as a right-handlatch, may be converted into a left-hand latch simply by substituting for the latch a lett-hand latch and by reversing the hub and the spring 9 about the axis of the casing.

I declare that what l claim is l. A lock, comprising a substantially cylindrical casing; a latch slidably litted therein; a spring Jor moving the latch outwardly off the casing; a hub rotatably mounted in said casing 'in rear oit said spring and` having means for retractingvthe latch; and a spiral spring, separate from the iii-st spring, dis* posed between the latter and the hub in a vertical plane axial of the casing, with its Y axis intersecting the casing axis, said spiral spring directly engaging said hub to return the same to normal position independently the position of the latch.

A lock, comprising a substantially 'cylindrical casing having a central, longitudinal slot; a latch slidably fitted in the cas ing and formed with a rearwardly-extending tail terminating in a vertical guide lug which projects into said slot, said tail being provided with a slot located in line with'the iirst slot and immediately in front of said lug; a spring operative on said latch to project it outwardly of the casing; and a hub rotatably mounted in said casing and having a iinger which extends through the latch slot to engage said lug andthereby retract the latch when the hub is rotated in one direction.

A lock, comprising a substantially cylindrical casing having a central, longitudinal slot; a latch slidably iitted in the casing and formed with a rearwardly-extending tail terminating in a vertical guide lug which f projects into said slot, said tail being provided with a slot located in line with the first slot and immediately in front of said lug; a spring operative on said latch to pro ject it outwardly of the casingg'a hub rotatably mounted in the casing and having a pair of fingers, one directed upwardly and the other directed downwardly, one of said lingers extending through the latch slotto engage said lug and thereby retract the latch when the hub is rotated in one direction;V

and a spring, separate from the first spring, operative upon the other linger Lto return said hub toV normal position independently ot the position of the latch. Y Y y I LL. A lock, as claimed in claim 3, in which the second-named spring has the lliorniof a vspiral and is located between thelirstl spring and the hub in a vertical plane which is axial ot' Lthe casing, with its axis intersecting the casing axis.

in `testimony whereof- I aiiix my signature. JOHi'iNNlS EHRHRN V HJURT.

lilitnesses CARL MnrirNGsnN, loir EN s in VVoLFF. 

